The invention relates to the field of deicers for inhibiting atmospheric ice accumulation on aircraft structures. More particularly, the invention relates to the bonding of a deicer to an aircraft structure.
Atmospheric ice accumulation on the ground and in flight has long been recognized as a serious hazard. Various deicing and anti-icing devices have been developed to safely remove or prevent unwanted ice accumulations on the external surfaces of aircraft. Many of these devices comprise deicers that are bonded to existing external surfaces using a removable adhesive. A deicer based on this concept may thus be removed and replaced if it fails or becomes damaged. A very common adhesive used for this purpose is catalogue number 1300L available from the Minnesota Mining and Manufacturing Company, St. Paul, Minn., U.S.A. Previous deicers that have been applied in this manner include elastomeric pneumatic deicers, elastomeric electrothermal deicers and anti-icers, and some electromechanical deicers.
Installation of a deicer using an adhesive such as 1300L involves applying the adhesive to the aircraft structure and to a bonding surface of the deicer. The adhesive is permitted to dry and then activated by wiping it with a solvent such as toluene or methyl-ethyl-ketone (MEK). The adhesive behaves as a contact adhesive, and the deicer is then pressed against the aircraft structure beginning with a selected area (such as a leading edge) and subsequently with increasing distance from the selected area. Rollers are preferably used to insure intimate contact between the two adhesive layers.
In spite of the widespread acceptance of this prior technique, a more durable adhesive interface between the deicer and the aircraft structure is generally desired. The adhesive interface must withstand attacks of sun, rain, deicing fluids, hydraulic fluids, turbine oils, and other degrading elements. In addition, prior commonly used adhesives have a very limited shelf life, and often contain toluol and MEK, as well as other potentially toxic chemicals. Various government agencies have placed severe restrictions on methods of shipping these adhesives, and on how the adhesives and solvents may be used. Finally, prior adhesives require several hours to cure before the deicers may be activated. Imposing several hours downtime on commercial operators is undesirable.
Though prior adhesives are certainly safe and suitable for attaching deicers to aircraft structures, an improved adhesive for this special purpose is desired. In particular, a strong and durable adhesive with good environmental resistance is generally desired. An adhesive having longer shelf life, and not containing or requiring use of solvents in the field is generally desired. Finally, an adhesive that bonds a deicer in a manner that accommodates minimum downtime is desired. The specific problem at hand is to provide a self-adhering deicer having the enumerated adhesive characteristics.